From: Sam Ravnborg <sam@ravnborg.org>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: b.zolnierkie@samsung.com, gwan-gyeong.mun@intel.com,
daniel.vetter@ffwll.ch, bernard@vivo.com,
laurent.pinchart@ideasonboard.com, linux-fbdev@vger.kernel.org,
dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drivers/video: Fix -Wstringop-truncation in hdmi.c
Date: Sun, 1 Nov 2020 10:50:21 +0100 [thread overview]
Message-ID: <20201101095021.GE1166694@ravnborg.org> (raw)
In-Reply-To: <20201021121241.17623-1-tzimmermann@suse.de>
On Wed, Oct 21, 2020 at 02:12:41PM +0200, Thomas Zimmermann wrote:
> Trying to copy into the string fields with strncpy() gives a warning from
> gcc. Both fields are part of a packed HDMI header and do not require a
> terminating \0 character.
>
> ../drivers/video/hdmi.c: In function 'hdmi_spd_infoframe_init':
> ../drivers/video/hdmi.c:230:2: warning: 'strncpy' specified bound 8 equals destination size [-Wstringop-truncation]
> 230 | strncpy(frame->vendor, vendor, sizeof(frame->vendor));
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> ../drivers/video/hdmi.c:231:2: warning: 'strncpy' specified bound 16 equals destination size [-Wstringop-truncation]
> 231 | strncpy(frame->product, product, sizeof(frame->product));
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Just use memcpy() instead.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
I assume vendor is guaranteed to be 0-termindated.
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
> ---
> drivers/video/hdmi.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
> index b7a1d6fae90d..1e4cb63d0d11 100644
> --- a/drivers/video/hdmi.c
> +++ b/drivers/video/hdmi.c
> @@ -221,14 +221,18 @@ EXPORT_SYMBOL(hdmi_avi_infoframe_pack);
> int hdmi_spd_infoframe_init(struct hdmi_spd_infoframe *frame,
> const char *vendor, const char *product)
> {
> + size_t len;
> +
> memset(frame, 0, sizeof(*frame));
>
> frame->type = HDMI_INFOFRAME_TYPE_SPD;
> frame->version = 1;
> frame->length = HDMI_SPD_INFOFRAME_SIZE;
>
> - strncpy(frame->vendor, vendor, sizeof(frame->vendor));
> - strncpy(frame->product, product, sizeof(frame->product));
> + len = strlen(vendor);
> + memcpy(frame->vendor, vendor, min(len, sizeof(frame->vendor)));
> + len = strlen(product);
> + memcpy(frame->product, product, min(len, sizeof(frame->product)));
>
> return 0;
> }
> --
> 2.28.0
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
next prev parent reply other threads:[~2020-11-01 9:50 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-21 12:12 [PATCH] drivers/video: Fix -Wstringop-truncation in hdmi.c Thomas Zimmermann
2020-10-21 23:06 ` Laurent Pinchart
2020-10-22 7:01 ` Thomas Zimmermann
2020-11-01 9:50 ` Sam Ravnborg [this message]
2020-11-01 16:43 ` Thomas Zimmermann
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